Compressed gas actuated electrical switch with sleeve valves

ABSTRACT

An electrical circuit breaker of the gas blast type includes a double-acting cylinder having the piston element connected to one of the contact members for opening and closing the circuit through the breaker respectively each time the piston is actuated in one direction or the other by successive opening operations of a gas blast valve which functions to deliver high-pressure gas to the circuit breaker contacts and also to one or the other of inlet ports located at opposite ends of the cylinder. The cylinder includes a reversing sleeve valve actuated by movement of the piston in one direction so as to ready the cylinder for piston movement in the opposite direction the next time that the blast valve is opened.

United States Patent [72] Inventor Dieter Floesiel Flsllsbach, Switzerland [2 l I Appl, No. 10,052 [22] Filed Feb. 12, 1970 [45] Patented Aug. 3, 1971 I73] Assignee Alttienleaelhdnlt Brown, Boveri 8: Cie

Bed. Switzerland [32] Priority Feb. 18, 1969 [33] Switzerhnd [31] 2,412/69 [54] COMPRESSED GAS AC'I'UATED ELECTRICAL SWITCH WITH SLEEVE VALVES 4 Claims, 2 Drawing Figs.

[52] 1.1.5. Cl 20-0/148 R, 251/634, 200/82 B [51] Int. Cl ..H0ll|33/54, H0lh 33/83 [50] Field 01 200/82 B, 148 11,148 D, 148 BU; 25 1163.4, 63.5, 62

[56] References Cited UNITED STATES PATENTS 3,436,505 4/1969 McKeough 200/148 R FOREIGN PATENTS Primary Examiner- Robert K. Schaefer Assistant Examiner- Robert A. Vanderhye Anomey-Pierce, Scheffler & Parker ABSTRACT: An electrical circuit breaker of the gas blast type includes a double-acting cylinder having the piston element connected to one of the contact members for opening and closing the circuit through the breaker respectively each time the piston is actuated in one direction or the other by successive opening operations of a gas blast valve which functions to deliver high-pressure gas to the circuit breaker contacts and also to one or the other of inlet ports located at opposite ends of the cylinder. The cylinder includes a reversing sleeve valve actuated by movement of the piston in one direction so as to ready the cylinder for piston movement in the opposite direction the next time that the blast valve is opened.

COMPRESSED GAS ACTUATED ELECTRICAL SWITCH WITH SLEEVE VALVES The present invention relates to electrical circuit breakers of the gas blast type which include at least one switching point constituted by a pair of relatively movable contact members located in a normally low-pressure chamber. A blast of gas at high pressure is fed to the contact chamber through a blast valve in order to open the circuit through the contact members and a similar gas blast is utilized in order to reclose the circuit. The movable contact member is actuated to open and closed position by means of a gas-operated reversing mechanism which is readied at the end of each movement of the contact member in one direction to operate the contact member in the opposite direction at the next gas blast. Circuit breakers of this general type are already known, reference being made to the structure disclosed in German Pat. No. 1,023,507 in which a three-way valve cock is operated by a transmission gearing in conjunction with a stepping mechanism.

The principal object of the present invention is to provide a more simple and advantageous construction for the gasoperated reversing mechanism. More particularly, the blast valve is constnicted as a sleeve valve which opens briefly during each operation of the circuit breaker, i.e., from closed to open position of the contacts, or vice versa, to admit highpressure gas to the switch contact chamber and also into one or the other end of a double-acting cylinder containing a piston that drives a piston rod in a corresponding direction and which is connected by suitable linkage to the movable contact member of the circuit breaker, so as to open the breaker contacts when the piston and piston rod move in one direction, and to close the breaker contacts when movement of the piston and piston rod is in the opposite direction. Gas admission into the cylinder at one end or the other is controlled by a reversing sleeve valve located within the cylinder and which forms the cylinder wall in engagement with the piston, the sleeve valve being shifted by the piston from one control position to the other. The piston is also maintained stably in its end positions corresponding to the closed and open positions. respectively of the circuit breaker contacts by means of a spring loaded overcenter toggle mechanism. The improved construction in accordance with the invention has a number of advantages, among them being that the force required to be transmitted to the blast valve sleeve to initiate the breaker contact operating mechanism is quite small since only friction forces acting on the sleeve are required to be overcome. Moreover, the entire system is practically in a forcedree state in either of its two rest positions.

One suitable embodiment of the invention will now be described in detail and is illustrated in the accompanying drawings wherein:

FIG. la is a view in vertical central section of one switch contact chamber and the associated blast valve and reversing mechanism for the contacts of a dual switching point circuit breaker, the contact members being shown in closed circuit position; and

FIG. lb is a view similar to FIG. 1a but showing the contact members in open circuit position.

With reference now to the drawings, in order to simplify illustration of the invention, only one of the two switching points of the circuit breaker has been included, the other switching point being constituted by identical structure and which is located to the right of a central vertical axis through the tubular insulator column I on which the circuit breaker structure is mounted. The two switching points are connected electrically in series.

The circuit breaker structure includes a metallic housing 2 supported atop the insulator column 1 and extending laterally from this housing is a hollow insulator 3 which constitutes a switch chamber enclosing a contact structure of generally known type including a stationary contact pin 4 which is engageable by a movable nozzle contact assembly 5 which is spring loaded into engagement with the contact pin 4 when the contact members occupy their closed position. Gas at high pressure is caused to flow into and through the nozzle contact 5 when the contacts 4 and 5 separate, and the gas is discharged from nozzle contact 5 through a duct 20 into the lower part of housing 2 which is at relative low gas pressure. The housing part 2b which communicates with the interior of contact chamber 3 supports an upstanding annular chamber 6 which serves to store gas at high pressure and which surrounds a vertical cylinder 20 which is open at the bottom and in communication with the casing part 2b. The wall of this cylinder which constitutes the inner wall of annular chamber 6 is provided with a series of circumferentially spaced gas ports 2d which are adapted to cooperate with a similar circumferential arrangement of ports 7a in sleeve valve 7 which is actuated in a vertical direction by means of a rod 8, the valve sleeve being secured to the upper end of this rod which extends downwardly through casing 2 and through insulator column, I to the lower end thereof at which is located a driving mechanism of conventional construction and not therefore illustrated, this mechanism sewing to actuate the rod 8 down or up as the case may be to open or close the circuit breaker contacts. The portion of rod 8 which extends downwardly through the support column 1 is insulated, and is also guided at one or more vertically spaced points within the column if it is of great length.

Located within housing 2 and in vertical alignment with sleeve 2c and below the latter is a double-acting cylinder la in which is slidably mounted a reversing sleeve valve 10 and a piston 11 located inwardly of the sleeve valve. Cylinder 2e is provided with upper and lower high-pressure inlet ports 9 and intermediate exhaust ports 9 which communicate with the low-pressure portion of housing 2. Similarly, the sleeve valve 10 is provided with upper and lower ports 9a which are adapted to register with the upper and lower ports 9, 9' in cylinder 2e. The periphery of piston 11 engages and is slidable along the inner surface of sleeve valve HI, and the outer surface of sleeve valve 10 is slidably engaged with the inner surface of cylinder 2e. Moreover, piston 11 is adapted to engage an upper shoulder on sleeve valve 10 to hold the valve in the upper position shown in FIG. la, and similarly engages a lower shoulder I0b to hold the valve in the lower position shown in FIG. 1b.

Piston II is provided with a tubular piston rod which surrounds the rod 8 and extends in both directions through the upper and lower end walls of cylinder 2e. The upwardly extending part of piston rod 110 is secured to a link and lever-actuating mechanism consisting of links 12a and 12c and a lever 12b intermediate the links, the link being secured to a lateral extension arm from piston lla and the link 120 being secured to a horizontal guide rod 5a integral with the movable nozzle contact assembly 5. The downwardly extending part of piston rod 110 is articulated to a spring-loaded overcenter toggle link assembly 13 which functions to yieldingly position the piston rod Ila in each limit position. The toggle links 13 secured to piston rod 110 are thus seen to be inclined upwardly when piston rod 110 occupies its upper position (FIG. Ia) and are inclined downwardly when piston rod 110 occupies its lower position (FIG. lb). The rod 8 is provided with upper and lower stops 14a, 146 which are adapted to contact the upper and lower ends of piston rod 110 at the opposite limit positions of the piston r In both the contact-open and contact-closed positions of the circuit breaker, gas at low pressure exists within the interior of component parts 1, 2, 2a 2b and 7, and gas at high pressure exists in the storage chamber 6. A return of gas from the lowpressure chamber portions within casing 2 to the high-pres sure chamber 6 can be effected in known manner by means which may include, if necessary a temperature-controlled compressor.

The circuit breaker structure operates in the following manner:

If the circuit breaker contact members 4 and 5 occupy their closed position as shown in FIG. la, and it is desired to open them, rod 8 is actuated downwardly in the direction indicated by the arrow. As valve sleeve 7 is drawn downwardly, the ports 7a come into registry with the ports 2d during an intermediate portion of the complete stroke of valve 7 with the result that gas at high pressure is ported through these ports, thence downwardly through sleeve 2c into the housing part 2b and thence into switch chamber 3 to the junction point of the closed contacts 4,5. High-pressure gas also arrives simultaneously at the upper ports 9, 9a which are then in registry so that the high-pressure gas flows into cylinder 2e and is applied to the upper surface of piston ll thus driving the piston and its piston rod lla downwardly. Downward movement of piston rod 110 then actuates the link-lever system [20, 12b, He thus drawing the nozzle contact member 5 to the right and separating it from the stationary contact pin 4. Upon withdrawal of nozzle contact member 5 from pin 4, the high-pressure gas within chamber 3 then passes into the gap between them to blast and extinguish the are drawn between the contacts. The gas then passes through the nozzle contact 5 and through duct 2a into the lower low-pressure part of casing 2.

As piston ll moves downwardly, gas within the cylinder beneath the piston is discharged into the low-pressure casing part 2 through the lower port 9a in sleeve valve 10 and the lower discharge port 9' in sleeve 2e. Piston ll then engages the lower shoulder 10b of sleeve valve 10 and shifts this sleeve to its opposite limit position as depicted in FIG. lb in which the lower ports 9, 9a are then in registry, as are also the upper ports 9', 9a. This also imparts a certain amount of damping to the piston movement so that the latter is braked gently to its final rest position as shown in FIG. lb. As the piston rod lla moves downwardly, it also assists in shifting the sleeve valve 7 to its lowermost position as shown in FIG. lb by engaging stop 14b temporarily, in which position it will be noted that the valve ports 70 are below the ports 2d in sleeve 2c. The lower position of sleeve valve 7 i determined by the stop 140 on rod 8 which is then in abutment with the upper end of piston rod 110, the latter being held in its lower position by the overcenter toggle mechanism 13. The toggle mechanism 13 is stressed for only a fraction of a second. It serves to prevent vibration of the drive during the period which the various chambers require for ventilation and pressure equalization.

in order to effect a closure of the circuit breaker contacts from the position shown in FIG. 1b to that shown in FIG. la, the rod 8 is actuated in the upward position in the direction of the arrow. This movement raises sleeve valve 7 so that ports 70 again come into registry with ports 2d for a short time as the valve sleeve moves upwardly, thus admitting high-pressure gas to housing 2b from whence it flows through the lower ports 9, 90 against the lower face of piston 11 thus driving piston rod lla upward to actuate the link-lever system 120 to 12c and drive the movable contact assembly 5 to the left so as to reengage the contact pin 4 and close the circuit. Piston ll also ultimately engages the upper shoulder 10a on sleeve valve 10 to reverse the sleeve to the upper limit position as shown in FIG. 10, thus restoring all components to a position of rest ready for the next opening operation of the breaker contacts.

Due to the relatively small amount of force required to actuate the sleeve valve 7, the compressive stress imposed upon the relatively long rod 8 to start its movement can easily be tolerated. particularly when the rod is guided at axially spaced points along its length. The actuating rod 8 can also serve, in an advantageous manner to indicate the switch position at ground level since its end positions are clearly associated with the "on" and "off" circuit breaker positions.

lclaim:

l. in an electrical circuit breaker of the gas blast type, the combination comprising at least one switching point established by a pair of contact members, at least one of said contact members being movable for opening and closing a circuit through the members as the members disengage and engage, respectively, a chamber structure enclosing said contact members, a housing, said housing being lll communication with said contact chamber structure and being at a low gas pressure when said contact members occupy their engaged and disengaged positions, a storage chamber for high-pressure gas adjacent said housing, a blast valve structure including a sleeve valve, a rod secured to said sleeve valve for actuating the same, said sleeve valve being movable between two limit positions in which said valve is closed and the valve being tem porarily opened during an intermediate portion of the complete stroke of the valve to place said high-pressure gas storage chamber in communication with said housing and contact chamber, a double-acting cylinder located within said housing, said cylinder including inlet ports at the opposite ends thereof, a reversing sleeve valve slidable within said cylinder, at double-acting piston slidable within said sleeve valve, a piston rod connected to said piston, and linkage means connecting said piston rod to said movable contact member for operation thereof such that said contact members are engaged and disengaged respectively when said piston occupies respective limit positions at opposite ends of said cylinder, said reversing sleeve valve being entrained by piston movement in each direction to shift said sleeve valve between limit positions at opposite ends of said cylinder and place the opposite end surfaces of said piston respectively in communication with the inlet ports at the opposite ends of said cylinder opening to said housing thereby to effect an actuation of said piston first in one direction and then in the other upon successive actuations of said blast valve to admit high-pressure gas into said housing.

2. An electric circuit breaker of the gas blast type as defined in claim 1 wherein said piston rod is hollow and said rod for actuating said sleeve valve for controlling admission of highpressure gas into said housing passes through said hollow piston rod.

3. An electric circuit breaker of the gas blast type as defined in claim I and which further includes means for maintaining said piston rod in one of its two limit positions prior to being actuated to its other limit position.

4. An electric circuit breaker of the gas blast type as defined in claim 1 wherein said piston rod is hollow, said rod for actuating said sleeve valve for controlling admission of high pressure gas into said housing passes through said hollow piston rod, stop means on said rod engageable with said piston rod for limiting movement of said rod in each direction of movement, and means for maintaining said piston rod in one of its two limit positions prior to being actuated to its other limit position. 

1. In an electrical circuit breaker of the gas blast type, the combination comprising at least one switching point established by a pair of contact members, at least one of said contact members being movable for opening and closing a circuit through the members as the members disengage and engage, respectively, a chamber structure enclosing said contact members, a housing, said housing being in communication with said contact chamber structure and being at a low gas pressure when said contact members occupy their engaged and disengaged positions, a storage chamber for high-pressure gas adjacent said housing, a blast valve structure including a sleeve valve, a rod secured to said sleeve valve for actuating the same, said sleeve valve being movable between two limit positions in which said valve is closed and the valve being temporarily opened during an intermediate portion of the complete stroke of the valve to place said highpressure gas storage chamber in communication with said housing and contact chamber, a double-acting cylinder located within said housing, said cylinder including inlet ports at the opposite ends thereof, a reversing sleeve valve slidable within said cylinder, a double-acting piston slidable within said sleeve valve, a piston rod connected to said piston, and linkage means connecting said piston rod to said movable contact member for operation thereof such that said contact members are engaged and disengaged respectively when said piston occupies respective limit positions at opposite ends of said cylinder, said reversing sleeve valve being entrained by piston movement in each direction to shift said sleeve valve between limit positions at opposite ends of said cylinder and place the opposite end surfaces of said piston respectively in communication with the inlet ports at the opposite ends of said cylinder opening to said housing thereby to effect an actuation of saId piston first in one direction and then in the other upon successive actuations of said blast valve to admit high-pressure gas into said housing.
 2. An electric circuit breaker of the gas blast type as defined in claim 1 wherein said piston rod is hollow and said rod for actuating said sleeve valve for controlling admission of high-pressure gas into said housing passes through said hollow piston rod.
 3. An electric circuit breaker of the gas blast type as defined in claim 1 and which further includes means for maintaining said piston rod in one of its two limit positions prior to being actuated to its other limit position.
 4. An electric circuit breaker of the gas blast type as defined in claim 1 wherein said piston rod is hollow, said rod for actuating said sleeve valve for controlling admission of high-pressure gas into said housing passes through said hollow piston rod, stop means on said rod engageable with said piston rod for limiting movement of said rod in each direction of movement, and means for maintaining said piston rod in one of its two limit positions prior to being actuated to its other limit position. 